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United States Patent |
6,147,180
|
Markel
,   et al.
|
November 14, 2000
|
Thermoplastic elastomer compositions from branched olefin copolymers
Abstract
The invention relates to a thermoplastic elastomer composition comprising a
branched olefin copolymer derived from olefinically unsaturated monomers
capable of insertion polymerization having A) a T.sub.g as measured by DSC
less than or equal to 10.degree. C.; B) T.sub.m greater than 80.degree.
C.; C) an elongation at break of greater than or equal to 300%; D) a
tensile strength of greater than or equal to 1,500 psi (10,300 kPa); and
E) an elastic recovery of greater than or equal to 50%. The invention also
relates to process for preparing the invention composition comprising: A)
polymerizing ethylene or propylene and optionally, one or more
copolymerizable monomers in a polymerization reaction under conditions
sufficient to form copolymer having greater than 40% chain end-group
unsaturation; B) copolymerizing the product of A) with ethylene and one or
more comonomers so as to prepare said branched olefin copolymer. The
branched olefin copolymer compositions of the invention are suitable as
replacements for styrene block copolymer compositions and in other
traditional thermoplastic elastomer applications.
Inventors:
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Markel; Eric J. (Kingwood, TX);
Weng; Weiqing (Houston, TX);
Dekmezian; Armen H. (Kingwood, TX);
Peacock; Andrew J. (Houston, TX)
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Assignee:
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Exxon Chemical Patents Inc. (Houston, TX)
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Appl. No.:
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019609 |
Filed:
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February 6, 1998 |
Current U.S. Class: |
526/352; 526/348; 526/351 |
Intern'l Class: |
C08F 210/02; C08F 210/06 |
Field of Search: |
526/351,352,348
|
References Cited
U.S. Patent Documents
3989768 | Nov., 1976 | Milkovich et al.
| |
4752597 | Jun., 1988 | Turner.
| |
4923833 | May., 1990 | Kioka et al.
| |
4999403 | Mar., 1991 | Datta et al.
| |
5272236 | Dec., 1993 | Lai et al.
| |
5391629 | Feb., 1995 | Turner et al.
| |
5444145 | Aug., 1995 | Brant et al.
| |
5475075 | Dec., 1995 | Brant et al.
| |
Foreign Patent Documents |
0 366 411 A2 | May., 1990 | EP.
| |
0 563 632 A1 | Oct., 1993 | EP.
| |
0 572 034 A2 | Dec., 1993 | EP.
| |
0 690 079 | Jan., 1996 | EP.
| |
0 727 446 A1 | Aug., 1996 | EP.
| |
0 791 626 A1 | Aug., 1997 | EP.
| |
4 337308 | May., 1991 | JP.
| |
2 241 244 | Jul., 1994 | GB.
| |
87 03604 | Jun., 1987 | WO.
| |
94 07930 A1 | Apr., 1994 | WO.
| |
94 21700 A1 | Sep., 1994 | WO.
| |
94 25523 A1 | Nov., 1994 | WO.
| |
97 06201 | Feb., 1997 | WO.
| |
Other References
"Structure And Properties of Block Polymers And Multiphass Polymer Systems:
An Overview of Present Status And Future Potential," Aggarwal, Sixth
Biennial Manchester Polymer Symposium, UMIST, (1976).
"Graft Polymers With Macromonomers. I. Synthesis From
Methacrylate-Terminated Polystyrene," Schulz, et al, J. of Applied Polymer
Science, vol. 27, pp. 4773-4786, (1982).
"Graft Polymers With Macromonomers. II. Copolymerization Kinetics Of
Methacrylate-Terminated Polystyrene And Predicted Graft Copolymer
Structures," Schulz, et al, J. of Polymer Science: Polymer Chemistry
Edition, vol. 22, pp. 1633-1652, (1984).
"Styrene/Isoprene Diblock Macromer Graft Copolymer: (Synthesis And
Properties," Schultz, et al, Ind. Eng. Chem. Prod. Res. Dev., Vol. 25, pp.
148-152 (1988).
"Graft Copolymer Compatibilizers For Blends Of Polypropylene And
Ethylene-Propylene Copolymers," Lohse, et al, Macromolecules, vol. 24, pp.
561-566, (1991).
"Theromplastics Elastomer Categories: A Comparison Of Physical Properties,
" Leggee, Elastomerics, vol. 123, No. 9, pp. 14-20 (1991).
"Relative Reactivities And Graft Distributions Of Polystyrene
Macromers.RTM. In Vinyl Chloride Copolymerization," Schulz, et al, Polymer
International, vol. 33, pp. 141-149, (1994).
|
Primary Examiner: Wu; David W.
Assistant Examiner: Lu; Caixia
Attorney, Agent or Firm: Muller; William G, Reid; Frank E.
Parent Case Text
This application is based on provisional applications U.S. Ser. No.
60/037323 filed Feb. 7, 1997, U.S. Ser. No. 60/046812 filed May 2, 1997,
and U.S. Ser. No. 60/067,782 filed Dec. 10, 1997.
Claims
We claim:
1. A thermoplastic elastomer composition comprising a branched olefin
copolymer derived from olefins capable of insertion polymerization, the
copolymer having A) a T.sub.g as measured by DSC less than or equal to
10.degree. C.; B) a T.sub.m greater than 80.degree. C.; C) an elongation
at break of greater than or equal to 300%; D) a Tensile Strength of
greater than or equal to 1,500 psi (10,300 kPa) at 25.degree. C.; and E)
an elastic recovery of greater than or equal to 50%.
2. The thermoplastic elastomer composition of claim 1 wherein said branched
olefin copolymer comprises sidechains derived from ethylene, optionally
with one or more copolymerizable monomers, such that the T.sub.g of the
sidechains is less than -10.degree. C., the T.sub.m of the sidechains is
greater than or equal to 80.degree. C., and the number-average molecular
weight is greater than 1,500 and less than 45,000.
3. The thermoplastic elastomer composition of claim 1 wherein said branched
olefin copolymer comprises sidechains derived from propylene, optionally
with one or more copolymerizable monomers, such that the T.sub.g of the
sidechains is less than 10.degree. C., the T.sub.m of the sidechains is
greater than or equal to 110.degree. C., and the number-average molecular
weight is greater than 1,500 and less than 45,000.
4. The thermoplastic elastomer of claim 1 prepared by the process
comprising: A) polymerizing ethylene or propylene, optionally with one or
more copolymerizable monomers, in a polymerization reaction under
conditions sufficient to form a polymer having greater than 40% chain
end-group unsaturation; and B) copolymerizing the product of A) with
ethylene and one or more copolymerizable monomers so as to prepare said
branched olefin copolymer.
5. The thermoplastic elastomer composition of claim 4 wherein step A) is
conducted by a solution process in which said ethylene and one or more
copolymerizable monomers are contacted with a transition metal olefin
polymerization catalyst activated by an alumoxane cocatalyst, the mole
ratio of aluminum to transition metal is less than 220: 1.
6. The thermoplastic elastomer composition of claim 5 wherein step B) is
conducted in a separate reaction by solution, slurry or gas phase ethylene
polymerization with an activated transition metal insertion polymerization
catalyst.
7. The thermoplastic elastomer composition of claim 4 wherein step A) and
step B) are conducted concurrently in the presence of a mixed catalyst
system comprising at least one transition metal olefin polymerization
catalyst capable of preparing ethylene copolymers having greater than 40%
chain end-group unsaturation and at least one transition metal olefin
polymerization catalyst capable of incorporating the ethylene copolymers
into said branched olefin copolymer.
Description
TECHNICAL FIELD
The invention relates to thermoplastic elastomer compositions comprised of
branched olefin copolymers having crystallizable polyolefin sidechains
incorporated into low crystallinity polyethylene backbones.
BACKGROUND ART
Triblock and multi-block copolymers are well-known in the art relating to
elastomeric polymers useful as thermoplastic elastomer ("TPE")
compositions due to the presence of "soft" (elastomeric) blocks connecting
"hard" (crystallizable or glassy) blocks. The hard blocks bind the polymer
network together at typical use temperatures. However, when heated above
the melt temperature or glass transition temperature of the hard block,
the polymer flows readily exhibiting thermoplastic behavior. See, for
example, G. Holden and N. R. Legge, Thermoplastic Elastomers: A
Comprehensive Review, Oxford University Press (1987).
The best commercially known class of TPE polymers are the styrenic block
copolymers (SBC), typically linear triblock polymers such as
styrene-isoprene-styrene and styrene-butadiene-styrene, the latter of
which when hydrogenated become essentially
styrene-(ethylene-butene)-styrene block copolymers. Radial and star
branched SBC copolymers are also well-known. These copolymers typically
are prepared by sequential anionic polymerization or by chemical coupling
of linear diblock copolymers. The glass transition temperature (T.sub.g)
of the typical SBC TPE is equal to or less than about 80-90.degree. C.,
thus presenting a limitation on the utility of these copolymers under
higher temperature use conditions. See, "Structures and Properties of
Block Polymers and Multiphase Polymer Systems: An Overview of Present
Status and Future Potential", S. L. Aggarwal, Sixth Biennial Manchester
Polymer Symposium (UMIST Manchester, March 1976)
Insertion, or coordination, polymerization of olefins can provide
economically more efficient means of providing copolymer products, both
because of process efficiencies and feedstock cost differences. Thus
useful TPE polymers from olefinically unsaturated monomers, such as
ethylene and C.sub.3 -C.sub.8 .alpha.-olefins, have been developed and are
also well-known. Examples include the physical blends of thermoplastic
olefins ("TPO") such as polypropylene with ethylene-propylene copolymers,
and similar blends wherein the ethylene-propylene, or
ethylene-propylene-diolefin phase is dynamically vulcanized so as to
maintain well dispersed, discrete soft phase particles in a polypropylene
matrix. See, N. R. Legge, "Thermoplastic elastomer categories: a
comparison of physical properties", ELASTOMERICS, pages 14-20 (September,
1991), and references cited therein.
The use of metallocene catalysts for olefin polymerization has led to
additional contributions to the field. U.S. Pat. No. 5,391,629 describes
thermoplastic elastomer compounds comprising tapered and block linear
polymers from ethylene and alpha-olefin monomers. Polymers having hard and
soft segments are said to be possible with single site metallocene
catalysts that are capable of preparing both segments. Examples are
provided of linear thermoplastic elastomers having hard blocks of high
density polyethylene or isotactic polypropylene and soft blocks of
ethylene-propylene rubber. Japanese Early Publication H4-337308(1992)
describes what is said to be a polyolefin copolymer product made by
polymerizing propylene first so as to form an isotactic polypropylene and
then copolymerizing the polypropylene with ethylene and propylene, both
polymerizations in the presence of an organoaluminum compound and a
silicon-bridged, biscyclopentadienyl zirconium dihalide compound.
Datta, et al (D. J. Lohse, S. Datta, and E. N. Kresge, Macromolecules 24,
561 (1991) described EP backbones functionalized with cyclic diolefins by
terpolymerization of ethylene, propylene and diolefin. The statistically
functionalized EP "soft block" was then copolymerized with propylene in
the presence of a catalyst producing isotactic polypropylene. In this way,
some of the "hard" block polypropylene chains were grafted through the
residual olefinic unsaturation onto the EP "soft" block as they were
formed. See also, EP-A-0 366 411. A limitation of this class of reactions,
in which chains with multiple functionalities are used in subsequent
reactions, is the formation of undesirable high molecular weight material
typically referred to as gel in the art. U.S. Pat. No. 4,999,403 describes
similar graft copolymer compounds where functional groups in the EPR
backbone are used for grafting isotactic polypropylene having reactive
groups. In both the graft copolymers are said to be useful as
compatibilizer compounds for blends of isotactic polypropylene and
ethylene-propylene rubber.
SUMMARY OF THE INVENTION
The invention relates to a thermoplastic elastomer composition comprising a
branched olefin copolymer derived from olefinically unsaturated monomers
capable of insertion polymerization having A) a T.sub.g as measured by DSC
less than or equal to 10.degree. C.; B) a melt temperature (T.sub.m)
greater than 80.degree. C.; C) an elongation at break of greater than or
equal to 300%, preferably greater than 500%; D) a Tensile Strength of
greater than or equal to 1,500 psi (10,300 kPa), preferably greater than
2,000 psi (13,800 kPa); and E) an elastic recovery of greater than or
equal to 50%. More particularly, the branched olefin copolymer is one that
comprises crystallizable sidechains derived from olefins, optionally with
one or more copolymerizable monomers, such that the T.sub.m is greater
than 80.degree. C., and the number-average molecular weight (M.sub.n) is
greater than 1,500 and less than 45,000. The invention thermoplastic
elastomer composition can be prepared by the process comprising: A)
copolymerizing an olefin, optionally with one or more copolymerizable
monomers, in a polymerization reaction under conditions sufficient to form
crystallizable or glassy copolymer having greater than 40% chain end-group
unsaturation; B) copolymerizing the product of A) with ethylene and one or
more copolymerizable monomers so as to prepare said branched olefin
copolymer. This thermoplastic elastomer composition exhibits elastic
properties comparable or superior to those of the traditionally important
SBC copolymers thus providing alternative means of feedstock sourcing and
industrial production for this important class of commercial products.
BRIEF DESCRIPTION OF FIGURES
FIG. 1 illustrates a comparison of measured physical properties of branched
olefin copolymers of the invention with a commercially available styrene
block copolymer thermoplastic elastomer.
DETAILED DESCRIPTION OF THE INVENTION
The thermoplastic elastomer compositions of this invention are comprised of
branched copolymers wherein both the copolymer backbone and polymeric
sidechains are derived from monoolefins polymerized under coordination or
insertion conditions with activated transition metal organometallic
catalyst compounds. The sidechains are copolymerized so as to exhibit
crystalline, semi-crystalline, or glassy properties suitable for hard
phase domains in accordance with the art understood meaning of those
terms, and are attached to a polymeric backbone that is less crystalline
or glassy than the sidechains, preferably, substantially amorphous, so as
to be suitable for the complementary soft phase domains characteristic of
thermoplastic elastomer compositions.
The crystallizable sidechains are comprised of chemical units capable of
forming crystalline or glassy polymeric segments under conditions of
insertion polymerization. Known monomers meeting this criteria are
ethylene, propylene, 3-methyl-1-pentene, and copolymers thereof, including
ethylene copolymers with .alpha.-olefin, cyclic olefin or styrenic
comonomers. Ethylene or propylene copolymer sidechains are preferable
provided that the amount of comonomer is insufficient to disrupt the
crystallinity such that the T.sub.m is reduced below 80.degree. C.
Suitable comonomers include C.sub.3 -C.sub.20 .alpha.-olefins or geminally
disubstituted monomers, C.sub.5 -C.sub.25 cyclic olefins, styrenic olefins
and lower carbon number (C.sub.3 -C.sub.8) alkyl-substituted analogs of
the cyclic and styrenic olefins. Thus, typically, the sidechains can
comprise from 85-100 mol % ethylene, and from 0-15 mol % comonomer,
preferably 90-99 mol % ethylene and 1-10 mol % comonomer, most preferably
94-98 mol % ethylene and 2-6 mol % comonomer. Alternatively, the
sidechains can comprise from 90-100 mol % propylene, and from 0-10 mol %
comonomer, preferably 92-99 mol % propylene and 1-8 mol % comonomer, most
preferably 95-98 mol % propylene and 2-5 mol % comonomer. In particular,
as the sidechain M.sub.n increases above about 3,000, it is preferable to
introduce small amounts of comonomer to minimize embrittlement, e.g.,
about 0.2-4.0 mol.% comonomer. The selection of comonomer can be based
upon properties other than crystallinity disrupting capability, for
instance, a longer olefin comonomer, such as 1-octene, may be preferred
over a shorter olefin such as 1-butene for improved polyethylene film
tear. For improved polyethylene film elasticity or barrier properties, a
cyclic comonomer such as norbornene or alkyl-substituted norbornene may be
preferred over an .alpha.-olefin.
The sidechains can have narrow or broad molecular weight distribution
(M.sub.w /M.sub.n), for example, from 1.1 to 30, typically 2-8.
Additionally, the sidechains can have different comonomer compositions,
e.g., including the orthogonal compositional distributions described in
U.S. Pat. No. 5,382,630 (CDBI>50%), incorporated by reference for purposes
of U.S. patent practice. Optionally, mixtures of sidechains with different
molecular weights and/or compositions may be used.
The M.sub.n of the sidechains are within the range of from greater than or
equal to 1,500 and less than or equal to 45,000. Preferably the M.sub.n of
the sidechains is from 1,500 to 30,000, and more preferably the M.sub.n is
from 1,500 to 25,000. The number of sidechains is related to the M.sub.n
of the sidechains such that the total weight ratio of the weight of the
sidechains to the total weight of the polymeric backbone segments between
and outside the incorporated sidechains is less than 60%, preferably
40-50%. Molecular weight here is determined by gel permeation
chromatography (GPC) and differential refractive index (DRI) measurements.
A preferred branched olefinic copolymer within this class will have an
enthalpy of fusion (.DELTA.H.sub.f) as measured by differential scanning
calorimetry of .ltoreq.90 cal/g (measured by integrating heat flows
recorded at temperatures .gtoreq.80.degree. C. while scanning at
.gtoreq.5.degree. C./min).
The backbone, or backbone polymeric segments, when taken together with the
sidechain interruption of the backbone structure, should have a lower
T.sub.m (or T.sub.g if not exhibiting a T.sub.m) than the sidechains. Thus
it will preferably comprise segments of chemical units not having a
measurable crystallinity, or having a T.sub.g lower than -10.degree. C.
The backbone segments as taken together typically will have a T.sub.m less
than or equal to 80.degree. C. and a T.sub.g less than or equal to
-10.degree. C. Elastomeric backbones will be particularly suitable, such
will be typically comprised of ethylene and one or more of C.sub.3
-C.sub.12 .alpha.-olefins or diolefins, particularly propylene and
1-butene. Other copolymerizable monomers include generally disubstituted
olefins such as isobutylene, cyclic olefins such as cyclopentene,
norbornene and alkyl-substituted norbornenes, and styrenic monomers such
as styrene and alkyl substituted styrenes. Low crystallinity backbones are
suitable, examples are high comonomer content ethylene copolymers (as
described before), e.g., >than 8 mol % comonomer.
As indicated above the mass of the backbone will typically comprise at
least 40 wt % of the total polymer mass, that of the backbone and the
sidechains together, so the backbone typically will have a nominal
weight-average molecular weight (M.sub.w) weight of at least equal to or
greater than about 50,000. The term nominal is used to indicate that
direct measurement of M.sub.w of the backbone is largely impossible but
that characterization of the copolymer product will exhibit measurements
of M.sub.w that correlate to a close approximate weight of the polymeric
backbone inclusive only of the monoolefin mer derivatives and the
insertion moieties of the sidebranches.
The branched olefin copolymers comprising the above sidechains and
backbones will typically have an M.sub.w equal to or greater than 50,000
as measured by GPC/DRI as defined for the examples. The M.sub.w typically
can exceed 300,000, preferably 200,000, up to 500,000 or higher.
The thermoplastic elastomer composition of the invention can be prepared by
a process comprising: A) copolymerizing ethylene or propylene, optionally
with one or more copolymerizable monomers, in a polymerization reaction
under conditions sufficient to form a copolymer having greater than 40%
chain end-group unsaturation, a T.sub.m .gtoreq.80.degree. C. and a
T.sub.g .ltoreq.10.degree. C.; B) copolymerizing the product of A) with
ethylene and one or more copolymerizable monomers so as to prepare said
branched olefin copolymer. For enthylene-based macromers prepared in step
A), the T.sub.g is preferably less than -5.degree. C., more preferably
less than -10.degree. C.
The process step A) can be usefully practiced in a solution process in
which ethylene and, optionally, one or more copolymerizable monomers, is
contacted with a transition metal olefin polymerization catalyst activated
by an alkylalumoxane cocatalyst, the mole ratio of aluminum to transition
metal being less than about 220:1. The terminally unsaturated copolymer
population so formed, with or without separation from copolymer product
having only saturated ends, can then be copolymerized with ethylene and
copolymerizable monomers in a separate reaction by solution, slurry or gas
phase ethylene polymerization with an activated transition metal insertion
polymerization catalyst, particularly a catalyst capable of incorporating
the ethylene copolymers into said branched olefin copolymer.
Alternatively, the process step A) can be practiced in a solution process
in which propylene and, optionally, one or more copolymerizable monomers,
is contacted with a stereorigid transition metal olefin polymerization
catalyst, one capable of producing stereregular polypropylene, activated
by any suitable cocatalyst, the reaction temperature kept at sufficiently
high levels so as to achieve significant populations of terminally
unsaturated polymer chains, e.g., greater than about 85.degree. C.,
preferably greater than about 90.degree. C. The terminally unsaturated
copolymer population so formed, with or without separation from copolymer
product having only saturated ends, can then be copolymerized with
ethylene and copolymerizable monomers, or other selection of monomers
suitable for the preparation of low crystallinity polymers, in a separate
reaction by solution, slurry or gas phase ethylene polymerization with an
activated transition metal insertion polymerization catalyst, particularly
a catalyst capable of incorporating the propylene copolymers into said
branched olefin copolymer having the low crystallinity backbone.
Conditions sufficient to form the sidechain ethylene copolymer include
using suitable ethylene and comonomer reactant ratios to assure the
described sidechain olefin-derived unit constitution, plus catalyst and
process conditions conducive to forming the unsaturated chain ends. The
teachings of copending provisional application U.S. Ser. No. 60/037323
filed Feb. 7, 1997 are specific to suitable catalyst selection and use to
prepare macromeric copolymer chains with a high yield of vinyl
unsaturation. The metallocene catalyst used in the step A) preparation of
the unsaturation-containing macromer can be essentially any catalyst
capable of insertion polymerization of ethylene, it can be one capable of
high comonomer incorporation capability (see below) or of low comonomer
incorporation capability. Those of low incorporation capability are
typically those that are more congested at the metal coordination site,
thus unbridged and substituted unbridged metallocene catalysts are
particularly suitable. See also the teachings of U.S. Pat. No. 5,498,809
and international publications WO 94/19436 and WO 94/13715, describing
means of preparing vinylidene-terminated ethylene-1-butene copolymers in
high yields. See also, the teachings of copending application U.S. Ser.
No. 08/651,030, filed May 21, 1996, U.S. Pat. No. 5,763,556 as to the
preparation of ethylene-isobutylene copolymers having high levels of
vinylidene chain-end unsaturation. Throughout the description above, and
below, the phrase "chain-end" or "terminal" when referring to unsaturation
means olefin unsaturation suitable for insertion polymerization whether or
not located precisely at the terminus of a chain. See also U.S. Pat. Nos.
5,324,801 and 5,621,054 addressing alternating ethylene-cyclic olefin
copolymers having crystalline melting points of 235.degree. C., and up,
macromers produced with the suitable catalysts of these descriptions will
have glassy attributes effective for functioning as the hard phase
component of the thermoplastic elastomers of this invention. All documents
of this paragraph are incorporated by reference for purposes of U.S.
patent practice.
In a particular embodiment, polymeric vinyl-containing, ethylene-containing
macromer product, suitable as branches for a subsequent copolymerization
reaction, can be prepared under solution polymerization conditions with
preferred molar ratios of aluminum in the alkyl alumoxane activator, e.g.,
methyl alumoxane (MAO), to transition metal. Preferably that level is
.gtoreq.20 and .ltoreq.175; more preferably .gtoreq.20 and .ltoreq.140;
and, most preferably .gtoreq.20 and .ltoreq.100. The temperature, pressure
and time of reaction depend upon the selected process but are generally
within the normal ranges for a solution process. Thus temperatures can
range from 20.degree. C. to 200.degree. C., preferably from 30.degree. C.
to 150.degree. C., and more preferably from 50.degree. C. to 140.degree.
C. The pressures of the reaction generally can vary from atmospheric to
345 MPa, preferably to 182 MPa. For typical solution reactions,
temperatures will typically range from ambient to 190.degree. C. with
pressures from ambient to 3.45 MPa. The reactions can be run batchwise.
Conditions for suitable slurry-type reactions are similar to solution
conditions except reaction temperatures are limited to those below the
melt temperature of the polymer. In an additional, alternative reaction
configuration, a supercritical fluid medium can be used with temperatures
up to 250.degree. C. and pressures up to 345 MPa. Under high temperature
and pressure reaction conditions, macromer product of lower molecular
weight ranges are typically produced, e.g., M.sub.n about 1,500.
In an alternative embodiment, polymeric vinyl-containing,
propylene-containing macromer product, suitable as branches for a
subsequent copolymerization reaction, can be prepared under solution
polymerization conditions with metallocene catalysts suitable for
preparing either of isotactic or syndiotactic polypropylene. A preferred
reaction process for propylene macromers having high levels of terminal
vinyl unsaturation is described in co-pending U.S. application 60/067,783,
filed Dec. 10, 1997, Attorney Docket No. 97B075. Typically used catalysts
are stereorigid, chiral or asymmetric, bridged metallocenes. See, for
example, U.S. Pat. No. 4,892,851, U.S. Pat. No. 5,017,714, U.S. Pat. No.
5,132,281, U.S. Pat. No. 5,155,080, U.S. Pat. No. 5,296,434, U.S. Pat. No.
5,278,264, U.S. Pat. No. 5,318,935, WO-A-(PCT/US92/10066), WO-A-93/19103,
EP-A2-0 577 581, EP-A1-0 578 838, and academic literature "The Influence
of Aromatic Substituents on the Polymerization Behavior of Bridged
Zirconocene Catalysts", Spaleck, W., et al, Organometallics 1994, 13,
954-963, and "ansa-Zirconocene Polymerization Catalysts with Annelated
Ring Ligands-Effects on Catalytic Activity and Polymer Chain Lengths",
Brinzinger, H., et al, Organometallics 1994, 13, 964-970, and documents
referred to therein.
Preferably, for isotactic polypropylene, the stereorigid transition metal
catalyst compound is selected from the group consisting of bridged
bis(indenyl) zirconocenes or hafnocenes. In a preferred embodiment, the
transition metal catalyst compound is a dimethylsilyl-bridged bis(indenyl)
zirconocene or hafnocene. More preferably, the transition metal catalyst
compound is dimethylsilyl (2-methyl-4-phenylindenyl) zirconium or hafnium
dichloride or dimethyl. In another preferred embodiment, the transition
metal catalyst is a dimethylsilyl-bridged bis(indenyl) hafnocene such as
dimethylsilyl bis(indenyl)hafnium dimethyl or dichloride. The method for
preparing propylene-based macromers having a high percentage of vinyl
terminal bonds involves:
a) contacting, in solution, propylene, optionally a minor amount of
copolymerizable monomer, with a catalyst composition containing the
stereorigid, activated transition metal catalyst compound at a temperature
from about 90.degree. C. to about 120.degree. C.; and
b) recovering isotactic or syndiotactic polypropylene chains having number
average molecular weights of about 2,000 to about 50,000 Daltons.
Preferably, the solution comprises a hydrocarbon solvent. More preferably,
the hydrocarbon solvent is aromatic. Also, the propylene monomers are
preferably contacted at a temperature from 95.degree. C. to 115.degree. C.
More preferably, a temperature from 100.degree. C. to 110.degree. C. is
used. Most preferably, the propylene monomers are contacted at a
temperature from 105.degree. C. to 110.degree. C. The pressures of the
reaction generally can vary from atmospheric to 345 MPa, preferably to 182
MPa. The reactions can be run batchwise or continuously. Conditions for
suitable slurry-type reactions will also be suitable and are similar to
solution conditions, the polymerization typically being run in liquid
propylene under pressures suitable to such. All documents are incorporated
by reference for purposes of U.S. Patent practice.
Additionally the invention branched olefin copolymer thermoplastic
elastomer composition can be prepared directly from the selected olefins
concurrently in the presence of a mixed catalyst system comprising at
least one first transition metal olefin polymerization catalyst capable of
preparing ethylene or propylene copolymers having greater than 40% chain
end-group unsaturation and at least one second transition metal olefin
polymerization catalyst capable of incorporating the ethylene or propylene
homopolymer or copolymer sidechains into said branched olefin copolymer.
This in situ method can be practiced by any method that permits both
preparation of unsaturated macromers having crystalline, semi-crystalline
or glassy properties and copolymerization of the macromers with comonomers
constituting the low crystallinity backbone such that the branched
copolymer is prepared. Gas phase, slurry and solution processes can be
used under conditions of temperature and pressure known to be useful in
such processes.
Suitable first catalyst compounds that when activated can achieve high
chain-end unsaturations specifically include those identified above with
respect to the preparation of high vinyl or vinylidene-containing
macromers. Preferably, catalysts that are active for ethylene
homopolymerization but do not incorporate higher carbon number monomers
appreciably, as discussed above, or do so only with attendant decrease in
M.sub.n, will be particularly suitable for the crystalline or glassy
sidechain preparation in the concurrent, or in situ, method of preparing
the invention thermoplastic copolymer compositions of the invention, so
long as the M.sub.n can be raised or maintained above the sidechain
minimum.
Suitable second catalyst compounds include those that are capable of good
comonomer incorporation without significant depression in M.sub.n, for the
polymeric backbone under the temperature and pressure conditions used. The
teachings of copending provisional application U.S. Ser. No. 60/037323
filed Feb. 7, 1997 are specific to suitable catalyst selection and use to
prepare branched olefin copolymers and addresses catalyst compounds
suitable for high comonomer and macromonomer incorporation. As indicated
therein, preferred catalyst compounds for assembling the branch olefin
copolymers from vinyl- or vinylidene containing macromers, ethylene and
copolymerizable comonomers include the bridged biscyclopentadienyl and
monocyclopentadienyl Group 4 metal compounds of U.S. Pat. Nos. 5,198,401,
5,270,393, 5,324,801, 5,444,145, 5,475,075, 5,635,573, International
applications WO 92/00333 and WO 96/00244; see also the unbridged
monocyclopentadienyl Group 4 metal compounds of copending application Ser.
No. 08/545,973, filed Oct. 20, 1995, ABN and the bis-amido and
bis-arylamido transition metal catalysts of U.S. Pat. No. 5,318,935 and
copending U.S. patent application Ser. No. 08/803,687, filed Feb. 24,
1997, and the .alpha.-diimine nickel catalyst complexes of WO 96/23010. In
accordance with these teachings, the transition metal catalyst compounds
are typically used with activating co-catalyst components as described,
e.g., alkyl alumoxanes and ionizing compounds capable of providing a
stabilizing non-coordinating anion. The teachings of each of the documents
of this paragraph are also incorporated by reference for purposes of U.S.
patent practice.
Industrial Applicability
The thermoplastic elastomer compositions according to the invention will
have use in a variety of applications wherein other thermoplastic
elastomer compositions have found use. Such uses include, but are not
limited to, those known for the styrene block copolymers, e.g.,
styrene-isoprene-styrene and styrene-butadiene-styrene copolymers, and
their hydrogenated analogs. Such include a variety of uses such as
backbone polymers in adhesive compositions and molded articles. These
applications will benefit from the increased use temperature range,
typically exceeding the 80-90.degree. C. limitation of the SBC copolymer
compositions. The compositions of the invention will also be suitable as
compatibilizer compounds for polyolefin blends. Additionally, due to the
inherent tensile strength, elasticity, and ease of melt processing,
extruded film, coating and packaging compositions can be prepared
comprising the invention thermoplastic elastomer compositions, optionally
as modified with conventional additives and adjuvents. Further, in view of
the preferred process of preparation using insertion polymerization of
readily available olefins, the invention thermoplastic elastomer
compositions can be prepared with low cost petrochemical feedstock under
low energy input conditions (as compared to either of low temperature
anionic polymerization or multistep melt processing conditions where
vulcanization is needed to achieve discrete thermoplastic elastomer
morphologies).
EXAMPLES
In order to illustrate the present invention, the following examples are
provided. Such are not meant to limit the invention in any respect, but
are solely provided for illustration purposes.
General: All polymerizations were performed in a 1-liter Zipperclave
reactor equipped with a water jacket for temperature control. Liquids were
measured into the reactor using calibrated sight glasses. High purity
(>99.5%) hexane, toluene and butene feeds were purified by passing first
through basic alumina activated at high temperature in nitrogen, followed
by 13.times.molecular sieve activated at high temperature in nitrogen.
Polymerization grade ethylene was supplied directly in a nitrogen-jacketed
line and used without further purification. Clear, 10% methylalumoxane
(MAO) in toluene was received from Albemarle Inc. in stainless steel
cylinders, divided into 1-liter glass containers, and stored in a
laboratory glove-box at ambient temperature. Ethylene was added to the
reactor as needed to maintain total system pressure at the reported levels
(semi-batch operation). Ethylene flow rate was monitored using a Matheson
mass flow meter (model number 8272-0424). To ensure the reaction medium
was well-mixed, a flat-paddle stirrer rotating at 750 rpm was used.
Reactor preparation: The reactor was first cleaned by heating to
150.degree. C. in toluene to dissolve any polymer residues, then cooled
and drained. Next, the reactor was heated using jacket water at
110.degree. C. and the reactor was purged with flowing nitrogen for a
period of .about.30 minutes. Before reaction, the reactor was further
purged using 10 nitrogen pressurize/vent cycles (to 100 psi) and 2
ethylene pressurize/vent cycles (to 300 psi). The cycling served three
purposes: (1) to thoroughly penetrate all dead ends such as pressure
gauges to purge fugitive contaminants, (2) to displace nitrogen in the
system with ethylene, and (3) to pressure test the reactor.
Catalyst preparation: All catalyst preparations were performed in an inert
atmosphere with <1.5 ppm H.sub.2 O content. In order to accurately measure
small amounts of catalyst, often less than a milligram, freshly prepared
catalyst stock solution/dilution methods were used in catalyst
preparation. To maximize solubility of the metallocenes, toluene was used
as a solvent. Stainless steel transfer tubes were washed with MAO to
remove impurities, drained, and activator and catalyst were added by
pipette, MAO first.
Macromer synthesis: First, the catalyst transfer tube was attached to a
reactor port under a continuous flow of nitrogen to purge ambient air.
Next, the reactor was purged and pressure tested as outlined above. Then,
600 ml of solvent was charged to the reactor and heated to the desired
temperature. Comonomer (if any) was then added, temperature was allowed to
equilibrate, and the base system pressure was recorded. The desired
partial pressure of ethylene was added on top of the base system pressure.
After allowing the ethylene to saturate the system (as indicated by zero
ethylene flow), the catalyst was injected in a pulse using high pressure
solvent. Reaction progression was monitored by reading ethylene uptake
from the electronic mass flow meter. When the desired amount of macromer
had accumulated, ethylene flow was terminated and the reaction was
terminated by heating (.about.1 minute) to 150.degree. C. for 30 minutes.
At the end of the kill step, the reactor was cooled to the temperature
desired for the LCB block assembly reaction (below) and a macromer sample
was removed for analysis.
Assembly of LCB Block Structures. All long chain branched (LCB) olefin
copolymer assembly reactions were performed in toluene using ethylene at
100 psi and MAO-activated (C.sub.5 Me.sub.4 SiMe.sub.2 NC.sub.12
H.sub.23)TiCl.sub.2 catalyst. Butene was used as comonomer in most
syntheses, but select reactions were performed using norbornene comonomer
in order to generate samples used to quantify LCB content. Reaction was
terminated by methanol injection when the desired amount of polymer (total
accumulated mass) were produced. Ethylene uptake/reactor pressure drop was
observed to halt within about 10 seconds of injection. The product was
poured into an excess of isopropyl alcohol and evaporated to dryness. In
another example (Example 3), Cp.sub.2 ZrCl.sub.2 and (C.sub.5 Me.sub.4
SiMe.sub.2 NC.sub.12 H.sub.23)TiCl.sub.2 catalysts were used in
single-step, mixed metallocene syntheses where the macromers were prepared
concurrently with the backbone and incorporated therein.
Catalyst pairing. For the mixed metallocene in situ example, the
metallocene catalyst pair was selected such that both a good incorporating
catalyst and a poorer incorporating catalyst was used. For this
technology, the good incorporator will typically exhibit three times the
incorporation capability of the poor incorporator or, even more
preferably, five times the incorporation capability. Comonomer
incorporation capability is defined and measured for each catalyst
compound, for the purposes of the present invention, in terms of weight
percent butene incorporation using a defined standard reaction condition
as follows. A one liter autoclave reactor is purged 2 hours at 90.degree.
C. with high purity nitrogen. The system is next purged of nitrogen using
flowing ethylene. Next, 600 milliliters of toluene and 50 milliliters of
liquid butene are added. The system is allowed to equilibrate at
90.degree. C. Next, ethylene at 100 psig is added until the solution is
saturated. A milligram of catalyst is added to 0.5 milliliters of 10
weight percent MAO in a stainless steel addition tube in an inert
atmosphere glovebox. Depending on the reactivity of the catalyst, more or
less catalyst/MAO solution may be required to assure substantial levels of
polymerization without excessive reaction exotherms. The catalyst is
injected into the reactor using pressurized solvent. Reactor pressure is
maintained at 100 psig throughout reaction by adding ethylene as required.
The reaction is terminated before the reactant compositions inside the
reactor change substantially (<20% conversion, as determined by analysis
of the reaction product). Comonomer incorporation is measured by .sup.1 H
NMR and is reported as ethyl groups per 1000 carbon atoms.
Example 1
Catalyst Preparation. A stainless steel catalyst addition tube was prepared
as outlined above. An aliquot of 1 milliliter of 10% methylalumoxane (MAO)
solution in toluene was added, followed by 5 milliliters of a toluene
solution containing 16 milligrams of (C.sub.5 Me.sub.4 SiMe.sub.2
NC.sub.12 H.sub.23)TiCl.sub.2. The sealed tube was removed from the
glovebox and connected to a reactor port under a continuous flow of
nitrogen. A flexible, stainless steel line from the reactor supply
manifold was connected to the other end of the addition tube under a
continuous flow of nitrogen.
Macromer Synthesis. The reactor was simultaneously purged of nitrogen and
pressure tested using two ethylene fill/purge cycles (to 300 psig). Then,
the reactor pressure was raised to .about.40 psi to maintain positive
reactor pressure during setup operations. Jacket water temperature was set
to 90.degree. C. and 600 milliliters of toluene and 10 milliliters of
butene were added to the reactor. The stirrer was set to 750 rpm.
Additional ethylene was added to maintain a positive reactor gauge
pressure as gas phase ethylene was absorbed into solution. The reactor
temperature controller was set to 90.degree. C. and the system was allowed
to reach steady state. The ethylene pressure regulator was next set to 100
psig and ethylene was added to the system until a steady state was
achieved as measured by zero ethylene uptake. The reactor was isolated and
a pulse of toluene pressurized to 300 psig was used to force the catalyst
solution from the addition tube into the reactor. The 100 psig ethylene
supply manifold was immediately opened to the reactor in order to maintain
a constant reactor pressure as ethylene was consumed by reaction.
After 15 minutes of reaction, the reaction solution was quickly heated to
150.degree. C. for 30 minutes, then cooled to 90.degree. C. A sample of
the prepolymerized macromer was removed from the reactor.
LCB Block Copolymer Synthesis. A stainless steel catalyst addition tube was
prepared as outlined above. An aliquot of 0.5 milliliter of 10%
methylalumoxane (MAO) solution in toluene was added to the tube, followed
by 1 milliliter of a toluene solution containing 0.5 milligrams of
(C.sub.5 Me.sub.4 SiMe.sub.2 NC.sub.12 H.sub.23)TiCl.sub.2 per milliliter.
The sealed tube was removed from the glovebox and connected to a reactor
port under a continuous flow of nitrogen. A flexible, stainless steel line
from the reactor supply manifold was connected to the other end of the
addition tube under a continuous flow of nitrogen.
The reactor temperature controller was set to 90.degree. C. Next, 70
milliliters of butene were added to the macromer-containing reactor and
the system was allowed to reach thermal equilibrium. Ethylene was next
added to the system at 100 psig (total). After allowing the ethylene to
saturate the system (as indicated by zero ethylene flow), the catalyst was
injected in a pulse using high pressure solvent. Reaction progression was
monitored by reading ethylene uptake from the electronic mass flow meter.
Reaction was terminated by methanol injection after 15 minutes. The
product was poured into an excess of isopropyl alcohol and evaporated to
dryness. Total yield of LCB block copolymer was 42.6 grams.
Example 2
Catalyst Preparation. A stainless steel catalyst addition tube was prepared
as outlined above. An aliquot of 0.5 milliliter of 10% methylalumoxane
(MAO) solution in toluene was added, followed by 5 milliliters of a
toluene solution containing 8 milligrams of Cp.sub.2 ZrCl.sub.2. The
sealed tube was removed from the glovebox and connected to a reactor port
under a continuous flow of nitrogen. A flexible, stainless steel line from
the reactor supply manifold was connected to the other end of the addition
tube under a continuous flow of nitrogen.
Macromer Synthesis. The reactor was simultaneously purged of nitrogen and
pressure tested using two ethylene fill/purge cycles (to 300 psig). Then,
the reactor pressure was raised to .about.20 psi to maintain positive
reactor pressure during setup operations. Jacket water temperature was set
to 90.degree. C. and 600 milliliters of toluene and 2 milliliters of 80.6
weight percent norbomene in toluene were added to the reactor. The stirrer
was set to 750 rpm. Additional ethylene was added to maintain a positive
reactor gauge pressure as gas phase ethylene was absorbed into solution.
The reactor temperature controller was set to 90.degree. C. and the system
was allowed to reach steady state. The ethylene pressure regulator was
next set to 30 psig and ethylene was added to the system until a steady
state was achieved as measured by zero ethylene uptake. The reactor was
isolated and a pulse of toluene pressurized to 300 psig was used to force
the catalyst solution from the addition tube into the reactor. The 30 psig
ethylene supply manifold was immediately opened to the reactor in order to
maintain a constant reactor pressure as ethylene was consumed by reaction.
After 15 minutes of reaction, the reaction solution was quickly heated to
150.degree. C. for 30 minutes, then cooled to 90.degree. C. A sample of
the prepolymerized macromer was removed from the reactor.
LCB Block Copolymer Synthesis. A stainless steel catalyst addition tube was
prepared as outlined above. An aliquot of 0.5 milliliter of 10%
methylalumoxane (MAO) solution in toluene was added, followed by 1
milliliter of a toluene solution containing 1 milligram of (C.sub.5
Me.sub.4 SiMe.sub.2 NC.sub.12 H.sub.23)TiCl.sub.2 per milliliter. The
sealed tube was removed from the glovebox and connected to a reactor port
under a continuous flow of nitrogen. A flexible, stainless steel line from
the reactor supply manifold was connected to the other end of the addition
tube under a continuous flow of nitrogen.
The reactor temperature controller was set to 60.degree. C. Next, 60
milliliters of 80.6% norbornene in toluene were added and the system was
allowed to reach thermal equilibrium. Ethylene was next added to the
system at 100 psig (total). After allowing the ethylene to saturate the
system (as indicated by zero ethylene flow), the catalyst was injected in
a pulse using high pressure solvent. Reaction progression was monitored by
reading ethylene uptake from the electronic mass flow meter. Reaction was
terminated by methanol injection after 5 minutes. The product was poured
into an excess of isopropyl alcohol and evaporated to dryness. Total yield
of LCB block copolymer was 91.9 grams.
Example 3
Catalyst Preparation. A stainless steel catalyst addition tube was prepared
as outlined above. An aliquot of 1 milliliter of 10% methylalumoxane (MAO)
solution in toluene was added, followed by a toluene solution containing
0.25 milligrams of (C.sub.5 Me.sub.4 SiMe.sub.2 NC.sub.12
H.sub.23)TiCl.sub.2 and 5 micrograms of Cp.sub.2 ZrCl.sub.2. The sealed
tube was removed from the glovebox and connected to a reactor port under a
continuous flow of nitrogen. A flexible, stainless steel line from the
reactor supply manifold was connected to the other end of the addition
tube under a continuous flow of nitrogen.
In situ LCB Block Copolymer Synthesis. The reactor was simultaneously
purged of nitrogen and pressure tested using two ethylene fill/purge
cycles (to 300 psig). Then, the reactor pressure was raised to .about.40
psi to maintain positive reactor pressure during setup operations. Jacket
water temperature was set to 90.degree. C. and 600 milliliters of toluene
and 20 milliliters of butene were added to the reactor. The stirrer was
set to 750 rpm. Additional ethylene was added to maintain a positive
reactor gauge pressure as gas phase ethylene was absorbed into solution.
The reactor temperature controller was set to 90.degree. C. and the system
was allowed to reach steady state. The ethylene pressure regulator was
next set to 100 psig and ethylene was added to the system until a steady
state was achieved as measured by zero ethylene uptake. The reactor was
isolated and a pulse of toluene pressurized to 300 psig was used to force
the catalyst solution from the addition tube into the reactor. The 100
psig ethylene supply manifold was immediately opened to the reactor in
order to maintain a constant reactor pressure as ethylene was consumed by
reaction. Reaction was terminated by methanol injection after 7 minutes.
The product was poured into an excess of isopropyl alcohol and evaporated
to dryness. Total yield of LCB block copolymer was 18.5 grams.
Properties
Structural data for the select materials are listed in Table 1. In the case
of the first two elastomeric examples (1 and 2), the macromer was sampled
directly from the reactor and characterized by .sup.1 H-NMR and GPC, while
for example 3 (mixed metallocene synthesis), the properties of the
macromer and backbone were attributed from the corresponding single
metallocene reactions.
Tensile data were obtained at room temperature and 80.degree. C. according
to method ASTM D-412 (in FIG. 1, tensile strength at break at room
temperature and 80.degree. C. is reported in units of pounds per square
inch while elongation at break is reported as a percentage). Recovery was
measured at room temperature using sample specimens identical to those
used in ASTM D-412 test except the sample was stretched 150%, then
released for 10 minutes and the percent recovery to the original
dimensions measured directly using reference marks on the test sample.
Tensile data for select samples indicate the statistically branched LCB
block copolymer formulations exhibited tensile strengths which were equal
to or exceeded styrenic block copolymers (Kraton.RTM.), with elastic
recovery slightly defensive relative to Kraton.RTM., but well within
commercially useful limits (see Table 1 and FIG. 1). Tensile strength at
break is highest for the norbornene LCB block copolymer (4,011 psi)
whereas the best elastic recovery (89%) was observed in a
mixed-metallocene butene LCB block copolymer. Both the low molecular
weight (10K, Cp.sub.2 ZrCl.sub.2 catalyzed) and high M.sub.n (30-40K,
(C.sub.5 Me.sub.4 SiMe.sub.2 NC.sub.12 H.sub.23)TiCl.sub.2 -catalyzed)
macromer gave LCB block copolymers with useful properties.
The ethylene/butene LCB block copolymers exhibit elastomeric properties
superior to an EXACT.RTM. 4033 (Exxon Chemical Company) ethylene/butene
(E/B) random copolymer of similar density and equal or better to an
ENGAGE.RTM. 8100 (Dow Chemical Company) ethylene/octene (E/O) random
copolymer of similar density (Table 2). Comparison of the
ethylene/norbornene (E/NB) linear and E/NB LCB block counterparts indicate
the LCB block copolymer is somewhat defensive in most areas, due in part
to its much lower norbornene content. Of course, all of the LCB block
copolymers melt at much higher temperatures than their linear
counterparts, due to the crystallizable, low molecular weight branch
component. It is interesting to note that the LCB block copolymers retain
significant tensile strength even when heated above the melt temperature
of their amorphous component (see 80.degree. C. tensile data). The
observed high temperature strength may be due to multi-block-type networks
in which amorphous material is anchored to high density, high melting
zones by side chains.
Product characterization: The branched olefin copolymer product samples
were analyzed by GPC using a Waters 150C high temperature system equipped
with a DRI Detector, Shodex AT-806MS column and operating at a system
temperature of 145.degree. C. The solvent used was 1,2,4 trichlorobenzene,
from which polymer sample solutions of 0.1 mg/ml concentration were
prepared for injection. The total solvent flow rate was 1.0 ml/minute and
the injection size was 300 microliters. GPC columns were calibrated using
a series of narrow polystyrenes (obtained from Tosoh Corporation, Tokyo,
1989). For quality control, a broad standard calibration based on the
linear PE sample NBS-1475 was used. The standard was run with each 16-vial
carousel. It was injected twice as the first sample of each batch. After
elution of the polymer samples, the resulting chromatograms were analyzed
using the Waters Expert Ease program to calculate the molecular weight
distribution and M.sub.n, M.sub.w and M.sub.z averages.
Polymer Analyses. The molecular weight, comonomer content, and
unsaturated-group structural distributions of the reaction products are
reported in Table 2. Unsaturated-group concentrations (total olefins per
1,000 carbon atoms) as well as vinyl group selectivities were found to
increase with decreasing aluminum: metal ratios, all other factors being
equal. The reported olefin comonomer concentrations can be increased
further by decreasing the concentration of ethylene in solution (by
decreasing ethylene partial pressure or increasing temperature).
TABLE 2
__________________________________________________________________________
Comparison of Branch Copolymer Properties with Representative
LLDPE's.
Branch
Branch
Branch
ENGAGE .RTM.
EXACT .RTM.
copolymer copolymer copolymer 8100 4033
Property E/B (#1) E/NB (#2) E/B (#3) E/O E/B
__________________________________________________________________________
Density (g/ml)
0.887 >0.935
.887 0.870 0.880
ASTM D-1505
Comonomer 15.5 5.65 12.6 12.1 11.7
(mol % .sup.1 H NMR)
Melting Point 119.2 115.5 123.5 60 63
(.degree. C., DSC)
Tensile at Break 2401 4011 3054 1030 1780
psi (kPa), (16,500) (27,700) (21,000) (7,100) (12,300)
ASTM D-412
Elongation at 905 386 669 950 740
Break (%)
ASTM D-412
Recovery (%) 76 60 87 76 50
150% extension
__________________________________________________________________________
Note:
E = ethylene,
B = butene,
NB = norbornene,
O = octene.
TABLE 3
__________________________________________________________________________
Comparison of Branch Copolymer Properties with Commercial
Styrene Triblock Copolymer (FIG. 1)
Tensile Tensile
Strength Elongation Strength Elongation
(psi/kPa @ (% @ Recovery (psi/kPa @ (% @
Ex. # Reactor 25.degree. C.) 25.degree. C.) (% @ 25.degree. C.)
80.degree. C.) 80.degree. C.)
__________________________________________________________________________
1 Dual
4011/ 594 60 1544/ 386
27,000 10,600
2 Single 3054/ 669 87 351/ 505
21,100 2,400
Kraton .RTM. 4002/ 580 95 220/ 86
G 1652 27,600 13,500
__________________________________________________________________________
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